Abstracts
Abstract
Several leneoldal arorthosltlc bodies of probable Precaabrian aga, are swosed In northern Cape Breton Island within a central fault-banded block of quartzofeldspathlc (pelsses. One of these, the Red River anorthoslts coaplex Cell ka long and up to 1 ka Hide) ranges free anorthoslte to anorthositlc gabbro with hltfi Aljpa and Sr contents and large positive Eu anoaalles resulting aalnly froa plagloolase aocuailatlon.
Following an episode of polyphase deforaatlon and aaphlbollte facles aetaaorphlsa, a aonzodlorite-gabbro body of unknown age was Intruded Into both the anorthoslte and Its host rocks. The gsochealstry of this Intrusion Indicates that It Is calc-alkallne. Granite sheets, Intrusive Into the aonzodlorlte-gabbro body, do not appear to be coaagaatlc based upon the trace eleeent chealstry. These sheets aay be correlated with granitic plutons in the Cape North area which have been dated at 330 ±23 to.
RESUME
Plualeura aas&es anorthosltlquss, vralsaablableaent d'age precaabrien, affleurent de aanlere lentloulaire eu sein d'un aaas central de gneiss quartzofeldspathlque, borde par des failles, dans la nord m I'tte 0X1 Cap-Breton. Paral cellea-ei, le coapiexe d'anorthoslte de Red River (d'environ 11 ka da longueur et Jusqu'a 1 ka de largsur) s'etage des anorthosltes aux gabbros anorthosltlques, aontre de haute contenus en AI2P3 et Sr et a fouml des anoaalles 6levees en Eu resultant prlnclpalament de I'acouBulatlon des plagloclasee.
Aprte un episode de deforaatlon potyphasee et adtaaorphlsae au facles aaphibollte, un corps de Bcmzonlte et gabbro d'age Incomu e'est Introdult tant dans I 'anorthoslte que dans ses encalssants. la geochlile de cette Intrusion trahft urn nature calco-alcallne. La chlile des eleaents en traces tend a nler le coaagntlsae des granites en nappe Intruelfs dans le corps de nonzodlorlte-gabbro. Ceux-cl s'apparentent plutdt aux plutons granltlques dans la region de Cape North qui sent dates a 330 ±23 Ma.
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